Statsbygg – BIM Manual 1.2.1 1 Statsbygg BIM Manual 1.2.1 Statsbygg Building Information Modelling Manual Version 1.2.1 (SBM1.2.1) – Date: 2013-12-17 Statsbygg - P.O. box 8106 dep., N-0032 Oslo, Norway www.statsbygg.no/bim - [email protected]ENGLISH VERSION Illustrations: From Architectural Competition for new National Museum at Vestbanen, Oslo
98
Embed
Statsbygg BIM Manual 1.2 · This document is designated as the ^Statsbygg Building Information Modelling Manual - version 1.2.1 _, and is also referenced by the acronym ^SBM1.2.1
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
A. INTRODUCTION ................................................................................................................................................ 6
A.2 OUT OF SCOPE (INFORMATIVE) ...................................................................................................................................... 6
Type object .............................................................................................................................................................. 8
Participant role ........................................................................................................................................................ 8
B.2 BIM – GENERIC MODEL STRUCTURE REQUIREMENTS ........................................................................................................ 14
B.3 THE REQUIREMENT BIM FROM THE CLIENT .................................................................................................................... 26
C. DOMAIN SPECIFIC REQUIREMENTS (NORMATIVE) .......................................................................................... 30
C.11 BIM CONSTRUCTION AND AS BUILT REQUIREMENTS ..................................................................................................... 57
C.12 BIM FOR FACILITY MANAGEMENT AND OPERATIONS ..................................................................................................... 60
C.13 BIM FOR DECOMMISSIONING AND DISPOSAL ............................................................................................................... 61
Construction Stage ................................................................................................................................................. 64
FM and operations stage ....................................................................................................................................... 64
D.2 ANALYSES APPLIED BY STATSBYGG (INFORMATIVE) .......................................................................................................... 65
Consistency check (Architectural and Structural) .................................................................................................. 65
Verifying design area (all projects) ........................................................................................................................ 68
Security and circulation.......................................................................................................................................... 70
D.3 BUILDING INFORMATION MODELLING PRACTICE (NORMATIVE) ......................................................................................... 74
Before starting modelling ...................................................................................................................................... 75
How to make a good model ................................................................................................................................... 75
Common modelling mistakes and misconceptions ................................................................................................ 76
E. BUILDING INFORMATION MODELLING SPIN-OFF DELIVERABLES (INFORMATIVE) .......................................... 81
F. CLASSIFICATIONS (INFORMATIVE) .................................................................................................................. 83
G. PROJECT SPECIFIC CONTRACT ADDENDUM (INFORMATIVE) ........................................................................... 88
H. REFERENCES ................................................................................................................................................... 96
I. CHANGE LOG .................................................................................................................................................. 98
MAND = Mandatory requirement that shall/must be met; an absolute requirement of the specification.
REC = Recommended requirement that should be met; means that there be valid reasons in particular
circumstances for ignoring this, but the full implications must be understood and carefully weighed before
choosing a different course.
OPT = Optional requirement that may or can be taken into account - means that this is truly optional, i.e. it
is admissible and possible to take this into account, or to refrain from doing so.
NOT REC = Discouraged action/solution that should be avoided; means that there may be valid reasons in
particular circumstances when the particular behaviour is acceptable or even useful, but the full
implications should be understood and the case carefully weighed before choosing this course.
NOT = Prohibitive action/solution that shall/must NOT be carried out; means that the definition is an
absolute prohibition of the specification.
INFO = Information that should be noted.
(…) = Bracketed requirements are conditional; they indicate that IF one of several described alternative
solutions represents the current situation, THEN it is required according to the requirement type (MAND
or REC).
All requirement types are not necessarily used actively in this version of the document, but may be used in
future amendments.
A.6 Norwegian phrases and acronyms
For some phrases (terms) or acronyms the Norwegian wording is provided for reference when working on
Statsbygg projects. They are expressed in italics in square brackets, prefixed with “no:“ – e.g. [no:BTA].
B.1 Basic BIM requirements
Statsbygg – BIM Manual 1.2.1
10
B. Generic Requirements (Normative)
B.1 Basic BIM requirements
Statsbygg has defined the following set of “Basic BIM” requirements that apply to all BIM deliverables,
regardless of the BIM objective, Phase, Discipline, etc. – unless otherwise agreed in the project.
BIM deliverables – Main targets
Ref.# Subject Type Requirement and description
1. Open BIM
deliverable
MAND A digital 3D building information model (subsequently
denoted as “the BIM” or similar) based on object-based
design (using objects with properties and relationships) and
using open BIM standards/formats is a main deliverable.
This implies that the Model Element Authors (MEA) must
use a suitable object-oriented BIM authoring tool that
efficiently supports the specified open standards as defined
in this specification.
2. BIM objective(s) MAND The Basic BIM requirements shall be met regardless of the
BIM objective(s).
The BIM shall be modelled for the specific BIM objective(s)
specified in the project – expressed or implied.
If for some reason any of the BIM requirements cannot be
met by the modelling author or the BIM authoring tools
used by the modelling author, the client shall be notified and
a stopgap solution for providing the BIM information shall be
suggested by the modelling author.
BIM – Generic requirements
Ref.# Subject Type Requirement and description
3. Open digital
storage format for
BIM to be
submitted to client
MAND The BIM authoring tool must efficiently support import and
export in the open Industry Foundation Classes (IFC) BIM
format. The core model of IFC is an ISO specification –
ISO/PAS 16739.
The BIM shall be submitted to the client in IFC 2x3 format.
Both IFC STEP, Part 21 (.ifc extension) and ifcXML, Part 28
(.xml or .ifcxml extensions) files are accepted.
B.1 Basic BIM requirements
Statsbygg – BIM Manual 1.2.1
11
Ref.# Subject Type Requirement and description
4. IFC release to be
used
MAND Unless otherwise stated, IFC Release 2x3 (subsequently
denoted as IFC 2x3) open BIM format shall be used.
The client may opt to accept newer IFC versions than IFC
2x3, provided all relevant modelling author disciplines are
capable of efficiently supporting the newer version.
5. Entire IFC model
allowed
INFO It is permissible to use the entire IFC 2x3 model as published
on the following website:
http://www.buildingsmart-
tech.org/ifc/IFC2x3/TC1/html/index.htm
6. BIM authoring tool
information
MAND At project start-up MEAs shall inform the client about which
BIM authoring tool(s) that efficiently support IFC they are
intending to use for the project. This information shall
include:
1.1. Name of commercial CAD/BIM product
1.2. Version/release/build of product (e.g. “8.2”)
1.3. Any plugin/add-on relevant to IFC-based BIM generation (e.g. “IFC Plugin v 2.3”) that may apply
1.4. OS/platform used (e.g. 64 bit MS-Windows 7)
1.5. If there are plans for upgrading or replacing existing products/platforms during the project period, an indication shall be provided of what/when/how
1.6. If multiple products are used, an indication shall be provided of the scope of use and information as indicated above for each product.
If the modelling author intends to change BIM authoring
tools during the project period, the client must be informed
about such changes in advance.
Any BIM authoring tool that does not efficiently support IFC
import/export for fulfilling client BIM requirements can be
rejected by the client for use on the project.
7. Original digital
storage format for
BIM to be
submitted to client
MAND In addition to the IFC open format BIM – which is the main
deliverable - the original modelling format from the BIM
authoring tool used (e.g. *.rvt files from Revit or .pla from
Archicad) , inclusive of library objects in active use in the
All files in the same project should be assigned the same
GUID (Global Unique Identifier) and Name for IfcProject –
preferably by preserving the IfcProject.GUID provided in the
client’s Spatial Program IFC file – or by using the architect’s
GUID, for example.
MAND If the BIM Authoring tool does not support the preservation
of the GUID and hence the use of GUID as a primary key for
identifying the project is not possible, preserving a unique
project name is required. The project name can then be
used as a secondary key on a model server, for example,
when merging models in the same project, but with different
project GUIDs.
15. Site MAND Unless otherwise agreed in the project one and only one site
object (IfcSite) shall be present for each project.
MAND The site name (IfcSite.LandTitleNumber) shall contain the
official ID of the Cadastre [no:Matrikkel] - the Cadastral
Number.
INFO In Norway the government register “Matrikkelen” is held by
the Norwegian Mapping Authority [no:Statens kartverk].
INFO A complete Cadastral number [no:Matrikkelnummer] in
Norway consists of the following components:
knr – Municipality number [no:Kommunenummer]
gnr – Estate Registration Number [no:gårdsnummer]
bnr – Title Number [no:bruksnummer]
fnr – Leasehold Number [no:festenummer]
snr – Section Number [no:seksjonsnummer]
MAND The knr, gnr and bnr are mandatory parts of the Cadastral
Number.
B.2 BIM – Generic model structure requirements
Statsbygg – BIM Manual 1.2.1
16
Ref.# Subject Type Requirement and description
MAND In the IfcSite.LandTitleNumber the Cadastral number shall
be expressed according to the following naming scheme:
knr gnr bnr fnr snr
The format shall always follow this layout:
- The knr always has four digits, possibly with leading zeros
- The gnr, bnr, fnr and snr must not have leading zeros
- All fields must be included
- Fields not in active use shall be defined by a zero (0).
- knr, snr, bnr, and fnr fields are separated by a white space
- Do not use characters other than spaces and numbers
INFO Examples:
0904 200 2430 0 14 (fnr is unused)
0904 200 2430 1 0 (snr is unused)
0904 200 2430 0 0 (fnr and snr are both unused)
(REC) Unless otherwise stated in the project, the site shall contain
the proposed/designed site geometry for the entire site. In
certain cases one may want to express the present site
geometry (before making alterations to the project). In such
cases a naming convention expressing this should be agreed.
REC If partial models are created (e.g. for separate buildings) and
submitted as separate model files, all files should be
assigned the same GUID (Global Unique Identifier) and
Name for IfcSite – preferably by preserving the
IfcProject.GUID provided in the client’s Spatial Program IFC
file.
(MAND) The site may additionally have a Statsbygg “complex
number” [no.Kompleksnummer] if so required in the
project. If required this naming shall be captured in
IfcSite.Longname.
REC The Kompleksnummer is used as the traditional Statsbygg
grouping of buildings within a local area that is used for a
defined purpose, typically the campus of a university, a
prison area, etc. It is desirable to maintain this reference in
the BIM.
16. Buildings MAND One or more building objects (IfcBuilding) present on the
site shall reflect the number of distinct physical building
structures / blocks on the site.
B.2 BIM – Generic model structure requirements
Statsbygg – BIM Manual 1.2.1
17
Ref.# Subject Type Requirement and description
REC Generic guidelines for the creation of a building object:
Detached building / building block : Separate IfcBuilding
Extension building work when building construction is added immediately above, below or adjacent (contiguous) to the existing building: same IfcBuilding as existing building
Extension building work when building construction is added close to the existing building, but with a clearly defined building envelope of its own: separate IfcBuilding
Transitional building construction between separate building blocks: Separate IfcBuilding
If in doubt about the separation of building structures into
IfcBuilding objects, the client should be noted before
commencing modelling.
MAND The building ID shall be modelled using IfcBuilding
Pset_BuildingCommon.BuildingID and contain the official ID
/ Building number [no:Bygningsnummer] as assigned by the
relevant government body.
MAND In Norway the Building number is assigned by the
municipality in which the building is located. Each
municipality has assigned a numbering range that can be
used for the registration of new buildings.
INFO A complete Building number consists of the knr
(Municipality number) and the gbnr - Building number.
INFO Example: 1601 10469228 means ”1601 Trondheim
Municipality”, gbnr””10469228”.
MAND In the Pset_BuildingCommon.BuildingID the Building
number shall be expressed according to the following
naming scheme:
knr gbnr
The format shall always follow this layout:
- The knr always has four digits, possibly with leading zeros
- The gbnr must not have leading zeros
- Both fields must be included
- knr and gbnr fields are separated by a white space
- Do not use characters other than spaces and numbers
B.2 BIM – Generic model structure requirements
Statsbygg – BIM Manual 1.2.1
18
Ref.# Subject Type Requirement and description
REC If the BIM Authoring tool does not support the naming of
buildings, the building names (IfcBuilding.Name) can be left
blank or set to “default” or similar. In such cases the naming
of the building can be added to the IFC file on a model server
or in a suitable application/viewer that supports it. It can
even by added directly in an ASCII text editor for MEAs
familiar with the IFC schema.
REC The building should be given a descriptive name in
IfcBuilding.Name.
INFO Example: “Bergen Courthouse”
(MAND) The building may additionally have a Statsbygg building
number” [no.Byggnummer] if so required in the project. If
required this naming shall be captured in
IfcBuilding.Longname.
(REC) The Byggummer is used as the traditional Statsbygg ID for
buildings within a complex number [no: Kompleksnummer].
It is desirable to maintain this reference in the BIM.
17. Storeys
MAND One or more storey objects (IfcBuidingStorey) shall be
present for each building, reflecting the number of floor
levels in the building, including mezzanine floors and similar
structures that cover only parts of a full storey.
REC For mezzanines, stair landings and other “levels” in the
building where it is not obvious that a separate storey
should be defined, a project agreement must be drawn up in
respect of the conditions required for defining a new storey.
Normally a small mezzanine should not trigger a new storey
definition.
REC For mezzanine floors we recommend:
External walls are modelled in the underlying storey.
Internal walls, spaces, etc. that belong to the
mezzanine shall be modelled in the mezzanine floor.
MAND The storey names (IfcBuidlingStorey.Name) shall be an
integer number starting from “1” at the lowest floor level
and incrementing by one for each floor level – i.e. storey
numbers must not be negative even for storeys below
ground.
B.2 BIM – Generic model structure requirements
Statsbygg – BIM Manual 1.2.1
19
Ref.# Subject Type Requirement and description
INFO Example: 2 = Second lowest floor level; this level may be
below, at, or above terrain level.
(MAND) The storey may additionally have a Statsbygg document
“PA0602” type naming scheme if so required in the project.
If required this naming shall be captured in
IfcBuidlingStorey.Longname.
INFO The main principles for such naming of “PA0602” involve a
double leading zero (00) for storeys below terrain level,
counting “downwards” (with the lowest number for the
storey closest to terrain level), “01” for the first storey above
terrain (counting upwards above terrain level), and trailing
characters “M” for mezzanine, “K” for basement [no:kjeller],
“U” for sub-terrain storey [no:underetasje], “T” for roof
storey [no:takplan], and “S” for underground floor
[no:sokkeletasje]. Please refer to the actual “PA0602”
document for details.
REC The “PA0602” naming should also contain a descriptive text
for the storey, in the IfcBuidlingStorey.Longname.
INFO Example:
IfcBuidlingStorey.Longname=5M Mezzanine on the 5th Floor
MAND The entrance level shall be referenced by applying a
property set to the storey object
Pset_BuildingStoreyCommon.EntranceLevel and setting this
to TRUE for the main entrance storey. If multiple entrances
at different storey levels have the same status as “main”,
one and only one entrance must nevertheless be selected as
the entrance level.
INFO Normally this will be at terrain level on one side of the
building. If one entrance is used for the majority of public
access traffic, this entrance will normally be selected as
“main”.
REC Storeys above ground should be referenced by applying a
property set to the storey object
Pset_BuildingStoreyCommon.AboveGround and setting this
to TRUE for floor levels above ground (terrain level).
B.2 BIM – Generic model structure requirements
Statsbygg – BIM Manual 1.2.1
20
Ref.# Subject Type Requirement and description
18. Spaces – in general MAND Spaces shall be modelled with 3-dimensional space objects
(IfcSpace). Spaces shall exist for all areas that represent a
defined function, regardless of whether the space is
delimited by physical walls/slabs, cubicles or open space
areas.
MAND Unless otherwise specified spaces shall be modelled when
they fulfil the conditions for being “worthy of measurement”
according to the measurement rules contained in Norwegian
Standard NS 3940 Areal- og volumberegning av bygninger
(areas and volumes of buildings).
INFO Please refer to the detailed requirements for different types
of spaces below.
19. Spaces - functional INFO
The client’s spatial program lists the programmed (required)
functional spaces (FUA) [no:funksjonsareal] with their
functional space net areas (NTA) [no:nettoareal].
INFO The client’s spatial program is provided as an IFC file to
enable the designer’s BIM Authoring tool (BIM/CAD
program) to import the space objects and drag&drop them
within the space areas of the design solution, and preserve
the space function’s ID.
MAND Functional Spaces shall have the “Room Function Number”
(RFN) of the spatial program set in IfcSpace.Name (e.g.
“02.01.005”).
INFO The RFN represents the functional hierarchy of the project,
regardless of whether this is a single (only main functions) or
multiple level (main functions with one or more levels of
sub- functions). The spaces are represented within the
lowest level space sub-function.
INFO Example: A space “02.01.005” is the fifth space function
defined within sub-function 01 of main function 02.
INFO It is permissible to have multiple identical space names, if
multiple physical spaces are designed in the proposed design
to fulfil the space function of the RFN space program.
B.2 BIM – Generic model structure requirements
Statsbygg – BIM Manual 1.2.1
21
Ref.# Subject Type Requirement and description
20. Spaces - technical REC Service and technical spaces may be programmed in the
client’s spatial program. If they are not, important technical
and service spaces that affect inter-disciplinary planning
should be modelled (IfcSpace) as early as possible during
design, typically spaces like:
Refrigeration plant
Heating plant
Main ventilation room
Electrical transformer room
Main electrical distribution room
Diesel generator room
UPS supply room
They should be given a descriptive name in the Longname
attribute (IfcSpace.Longname).
21. Spaces – the gross
area object
MAND For each storey, information about the total gross area
[no:BTA – Bruttoareal] must be contained in a “BTA space
object” (IfcSpace). BTA is the area of each storey reaching
out to the exterior of all enveloping building parts (walls,
etc.). The precise definition is found in NS 3940. The sole
purpose of this “BTA” object is to express the total storey
area, including walls.
INFO The “BTA space object” will naturally overlap (“clash”) with
all other spaces in the storey.
(MAND) If the BIM Authoring tool does not support such an object as
being legal in the IFC export, the gross area for each storey
shall be expressed in the storey object or its property sets.
22. Spaces - external REC Outdoor space functions should be modelled in the BIM as
spaces (IfcSpace) even though they may not be physically
delimited by walls, etc., e.g. ground level parking spaces,
park and garden area functions, etc.
23. Spaces – without a
programmed area
INFO Some space functions (IfcSpace) in the client’s spatial
program may be listed without a programmed area when no
specific space area requirement has been set for the
function.
B.2 BIM – Generic model structure requirements
Statsbygg – BIM Manual 1.2.1
22
Ref.# Subject Type Requirement and description
MAND These areas will have the planned net and gross area set to
zero in the Pset_SpaceCommon property set. When these
program spaces are modelled in the design, the BIM real
design area shall be updated for the spacces.
24. Spaces – additions
in the design
process
INFO Some functions in the client’s space program may be listed
with only their main functions, i.e. their sub-functions may
need to be added / suggested by the design team architect.
MAND In such cases the architect shall generate relevant Room
Function Numbers (RFN) in the series of the relevant
function (e.g. “9.1.1.3” if this happened to be a non-RFN
sub-function in Chapter 9.1.1 of the spatial program).
MAND The design architect may also feel that some main functions
or sub-functions are missing and need to be added. In such
cases functions shall be added by allocating unused RFNs.
Such functions must be briefly described – preferably by
adding such in the IfcSpace.Longname attribute.
25. Spaces - functional
space heights
MAND Functional spaces (IfcSpace objects) shall be modelled from
the upper edge of a slab to the lower edge of slab above.
MAND Geometry shall be approximate in respect of shape, size
(length, width, height, area and volume), location and
orientation.
46. External
enclosure/building
envelope
MAND All spaces with climate/comfort requirements shall be
encircled by the building envelope.
REC The building envelope should be “airtight”.
MAND IfcWall.Name = Building code (no: NS3451) + User defined
wall type (e.g: 231 YV-01, or 231.01)
REC Type should be set according to defined types in the project.
User defined wall type description can be set in
IfcWall.Description, .Material or in a separate wall scheme.
C.1 Architecture Modelling [no:ARK]
Statsbygg – BIM Manual 1.2.1
31
Ref.# Subject Type Requirement and description
MAND
Objects in the building envelope like roof, exterior walls,
windows and doors (IfcWall, IfcCurtainWall, etc.) shall be
identified as external elements (e.g.
IfcWallCommon|IsExternal=true)
MAND The following properties shall not differ within the same wall
type:
Wall thickness
Material
MAND External wall height shall be according to planned floor
height, and modelled from the top surface floor slab in
storey n, to the bottom surface of slab in storey n+1.
47. Superstructure REC
The following load bearing building elements should be
modelled if the project or design requires it at such an early
phase:
Reinforced walls
Frameworks
Columns and beams
Footings
(MAND) These objects require the use of naming conventions or
object type including building code [no: NS3451]
Example:
IfcFooting.ObjectType=214.1 pelefundament,
IcfColumn.ObjectType=222.1 søyler
IfcWall.ObjectType= 224.3 avstivet vegg
48. Internal enclosure
walls
REC Internal walls should be included in the model. This
requirement is not mandatory because the project might
focus on overall volumes and design.
(MAND) Wall types should be set according to defined wall types in
the project. The following properties shall not differ within
the same wall type:
Wall thickness
Material
REC User defined wall type description should be set in
IfcWall.Description or in a separate wall schema.
REC Internal wall height should be modelled from the top surface
floor slab in storey n, to the bottom surface of slab in storey
n+1.
C.1 Architecture Modelling [no:ARK]
Statsbygg – BIM Manual 1.2.1
32
Ref.# Subject Type Requirement and description
REC Internal doors should be included in this phase, primarily for
visualisation purposes.
IfcDoor.Name = door code (e.g. 10M)
IfcDoor.Type = user defined label (e.g. ID-01)
PSet_IfcDoorCommon|IsExternal = false
PSet_IfcDoorCommon|FireExit = true/false
49. Floor slabs MAND At least one floor slab for each storey according to the
structural engineer [no: RIB]
Set type to correct IfcSlabTypeEnumeration=
’baseslab’ for slab on ground
‘floor’ for slab(s) between storeys
‘roof’ for top or roof slabs
MAND The following properties shall not differ within the same slab
type:
Slab thickness
Material
50. Major
equipment/invent
ory objects
REC
Equipment or inventory that are space-intensive, heavy and
prone to vibration or noise generation, have potential
structural consequences, etc. and thus affect inter-
disciplinary planning /design / engineering, should be
modelled using the relevant object entity types, with the
basic geometry at the approximate location.
INFO If component geometry is product specific and hard to
predict, ”bounding box” geometry should be applied for
space planning purposes.
REC For example, a laboratory unit, like a water tank, should be
modelled as:
IfcObject
IfcObject.Name = Water tank
IfcObject.ObjectType = Planned article number [01.242]
51. Stairs, elevators MAND Main stairs shall be modelled. Geometry is most relevant,
but circulation and/or regress analysis tests could be carried
out during this phase.
IfcStair.Name = User defined type (e.g. Stair 01)
IfcStair.Tag = User defined tag (e.g. F for FireExit)
IfcStair.Type = IfcStairTypeEnum /1/
C.1 Architecture Modelling [no:ARK]
Statsbygg – BIM Manual 1.2.1
33
Ref.# Subject Type Requirement and description
MAND Elevator shafts shall be modelled. Elevator shafts must
contain a space object within the shaft walls.
Example: IfcSpace.Name = Elevator [no: Heis]
Elevator shafts are part of the gross area of each storey
REC The elevator car should be modelled, preferably with type
enumeration.
Example:
IfcTransportElement
IfcTransportElementTypeEnum = ELEVATOR
INFO Net functional dimensions inside the elevator car are set in
Pset_TransportElementElevator
ClearWidth
ClearHeight
ClearLength
52. Functional area
spaces
MAND
Model contains all programmed areas with IfcSpace.Name =
RoomFunctionNumber (e.g. 01.02.019)
MAND Room name is set in IfcSpace.LongName
53. Technical area,
circulation and
gross area
MAND In addition to functional spaces (NS3940:FUA), the following
spaces must be modelled in this phase:
Technical room (NS3940:TEA)for ventilation (e.g.: IfcSpace.LongName = Main ventilation room)
Vertical ducts
Gross area [NS3940: BTA] for each storey
Circulation area (NS3940:KOA).
54. Zones INFO Requirements for zones are handled under the generic
requirements section.
REC If a zone denotes a (fire) compartment, the following types should be used, if applicable, as values of the ObjectType attribute:
FireCompartment - a zone of spaces, collected to represent a single fire compartment.
ElevatorShaft - a collection of spaces within an elevator, potentially going through many storeys.
RisingDuct
RunningDuct
C.1 Architecture Modelling [no:ARK]
Statsbygg – BIM Manual 1.2.1
34
Ref.# Subject Type Requirement and description
55. Space boundaries INFO Space boundaries (IfcRelSpaceBoundary) are virtual objects used to calculate quantities for various forms of analysis relating to spaces (IfcSpace) in buildings.
Analyses that use space boundaries include:
Quantity takeoff for Cost Estimating – In the early stages of design, many objects have not yet been modelled. During this phase of a project, space boundaries (and other measurements based on the space object) are used to estimate such things as finished materials (i.e. carpeting, tiles, paint) and casework.
Energy Analysis – i.e. estimating the amount of energy that will be used by a building during operation. Space boundary energy flows between a space and other spaces or the outside air.
Facilities Management Work Package Estimating – During the operational phase of a building’s life cycle, space boundaries can be used to estimate areas for facilities management work packages such as re-painting, carpet cleaning and the cleaning of other building element surfaces.
“First level” space boundaries are the boundaries of a space defined by the surfaces of building elements bordering this space (physical space boundaries) or by virtual surfaces provided by an adjacent space with no dividing wall.
“Second level” level space boundaries still represent building elements that border the space, but are more granular in that they are subdivided in any of the following cases: (a) Contained openings (with or without fillings like doors and windows), (b) Differences in materials and/or material assemblies (e.g. a wainscot or panelling on the lower portion of a wall), and (c) Differences in spaces or zones on the other side of the building element (or virtual boundary) represented by the space boundary (e.g. two different spaces on the other side of a wall).
REC Space boundaries should be included in the BIM whenever
the aim is to serve relevant purposes where space
boundaries are essential – second level if the BIM authoring
tool supports it.
Full Conceptual Design – Default modelling requirements
Ref.# Subject Type Requirement and description
56. Basis MAND
All architectural requirements from the Outline Conceptual
Design Phase apply as a basis for this phase.
C.1 Architecture Modelling [no:ARK]
Statsbygg – BIM Manual 1.2.1
35
Ref.# Subject Type Requirement and description
57. Geometric
accuracy
MAND Geometry shall be approximate in respect of shape, size
(length, width, height, area, volume), location and
orientation.
58. Building envelope,
superstructure
and façade
MAND All building elements shall be modelled with the relevant
object entities for occurrences (e.g. IfcWall) and type objects
(e.g. IfcWallType).
INFO Two windows of the same type (example):
Window 1:
IfcWindow.GUID= 3SY_hhw$P7xOyg0$CxruKE
IfcWindowType.GUID= 32LF0qsHPChwCP0g$H3TYJ
Window 2:
IfcWindow.GUID= 2tjoTk$WL6cBkoI9siTij3
IfcWindowType.GUID= 32LF0qsHPChwCP0g$H3TYJ
MAND Models shall contain cost-demanding coverings and special
equipment in the façade such as an external sun shield.
INFO How to model a sun protection system:
IfcBuildingElementProxyType.Name = Enum (no:
solavkjerming)
59. Internal enclosure,
walls and doors
MAND All internal walls shall be modelled with the following
attribute properties in PSet_WallCommon:
FireRating = FireEnum (e.g. EI60)
LoadBearing = TRUE/FALSE
IsExternal = TRUE/FALSE
AcusticRating = AcusticEnum (e.g. R’40)
Compartmentation = TRUE/FALSE
REC Other properties are optional. For definitions please visit IAI-
tech /2/
MAND All load bearing elements shall contain block-outs [no:
utsparinger] for technical ducts and shafts. Coordinate with
construction and mechanical domain.
(MAND) Internal doors must have the object type, and the following
attribute properties in PSet_DoorCommon:
FireRating = FireEnum (e.g. REI60)
FireExit = TRUE/FALSE
Other properties are optional.
60. Structure MAND Load bearing elements – e.g. columns, load bearing layers of
slabs and walls – shall be included and be modeled with
correct location and dimensions, in agreement with The
Structural Engineer.
(MAND) Column front cover [no: søyleforkant] has own wall type:
e.g. IfcWallType.Name = 222.1 column front cover
C.1 Architecture Modelling [no:ARK]
Statsbygg – BIM Manual 1.2.1
36
Ref.# Subject Type Requirement and description
INFO There must be a 100 % overlap of columns when
undertaking a collision check between an architectural and a
structural model.
61. Suspended ceilings MAND Suspended ceilings must be modelled at right height and
coordinated with the mechanical domain. Ceiling thickness is
approximate.
62. Sanitary
equipment
MAND Placement of sanitary equipment like water closet, sink and
kitchenette, etc.
REC Coordinate need for supply and outlets with mechanical
domain.
63. Inventory,
equipment and
other building
elements
MAND Furniture is modelled as IfcFurnishingElement. The name of
the type of furniture is defined using the
IfcFurnitureType.Name attribute. For the following types of
furniture naming shall be used: Chari, Table, Shelf Unit
E.g. IfcFurnitureType.Name = dining table, clothes closet,
refrigerator, lamp
(MAND) If using an article registry, such as dRofus equipment
database, the database number is set in tag:
IfcFurnitureType.Tag = 60.02.003
(MAND) If using IfcBuildingElementProxy objects, the following
naming scheme according to the infrastructure type shall be
used:
Building code (no: NS 3451) + Name of object
e.g. IfcBuildingElementProxy.Name = 265.X Cornice (no:
gesims)
64. Spaces MAND All planned spaces shall contain the room function number
and be placed in the model.
MAND In addition to functional spaces ,the following spaces must
be modelled in this phase:
All main technical areas
Vertical ducts [no: vertikale sjakter]
Running ducts [no: horisontale sjakter]
Gross area [no:BTA] for each storey
Circulation area
65. Zones MAND The model shall contain following zone types:
Fire zone
C.1 Architecture Modelling [no:ARK]
Statsbygg – BIM Manual 1.2.1
37
Ref.# Subject Type Requirement and description
REC Other zone types should be used, such as:
Security zone
Heating zone
Cooling zone
66. Stairs and
elevators
MAND All stairs, ramps, elevators and escalators shall be modelled.
(MAND) Properties and type definitions as in previous phase.
Coordinated design, procurement and full financial authority – Default modelling
requirements
Ref.# Subject Type Requirement and description
67. Basis MAND
All architectural requirements from the Full Conceptual
Design Phase apply as a basis.
68. Geometric
accuracy
MAND Geometry shall be accurate in respect of shape, size (length,
width, height, area, volume), location and orientation.
“Location” includes precise positioning within spaces for
relevant equipment and furniture.
69. External walls MAND
Wall objects shall contain material layers.
Texture is described in IfcWallType.Description
Slab and column front cover [no: dekke-, søyleforkant] and
roof cornice have their own wall type:
e.g. IfcWallType.Name = 226.3 slab front cover
70. Internal walls MAND
Wall objects contain material layers and the final height.
71. Suspended ceilings REC Suspended ceiling should be modelled as a slab with
IfcSlabType.Name = 257.X suspended ceiling
INFO Suspended ceilings do not contain a grid. This can be
formulated in IfcSlabType.Description
INFO [no: Skjørt] can be modelled in various approaches. Either by
wall or slab tools. Proxy elements can be used, but with
correct naming conventions
e.g.:
IfcBuildingElementType.Name = 245.X Skjørt or
IfcWallType.Name = 245.X Skjørt
C.2 Landscape Architecture Modelling [no:LARK]
Statsbygg – BIM Manual 1.2.1
38
Ref.# Subject Type Requirement and description
72. Windows and
doors
MAND
REC
The model shall contain internal and external doors,
modelled with the correct dimensions and placement.
Window (and door) fittings can be modelled as proxy
elements.
73. Spaces MAND All spaces in the model shall contain the room function
number, generated by the requirements database.
74. Zones MAND
OPT
The model shall contain the following zone types:
Fire zone (fire compartments)
Heating zone
Cooling zone
Other zone types should be used, such as:
Security zone
C.2 Landscape Architecture Modelling [no:LARK]
Generic requirements
Ref.# Subject Type Requirement and description
75. Landscape
architectural
requirements in
general
REC
Statsbygg currently does not have very specific BIM
requirements for Landscape Architecture deliverables, as the
integration of landscaping into BIM is considered an
emerging technology. In general Statsbygg recommends that
at least the geometry of the landscaping elements should be
exported to IFC by the use of CAD systems that can import
the format used for landscaping and then export it to IFC
geometry.
REC Statsbygg also recommends that the landscaping elements
are referenced to the same project zero as the other design
disciplines’ models, to enable merging of the models for
common visualisation.
INFO An overview is provided in the ASLA report entitled
“Integrating BIM Technology Into Landscape Architecture”
by James L. Sipes, ASLA – available for purchase or member
Statsbygg has currently identified the BIM objectives listed below – some of which are discussed while
others are headliners only.
The identified objectives are currently not all implemented and in use at Statsbygg, but rather a collection
of objectives identified and considered relevant to consider in projects. They appear on the list because
they have a potential “productivity effect” utilising open BIM data exchange for one or more stakeholders
in the AEC value chain.
Pre-Design stage
1. Alternative sites analysis (multiple sites assessment) [this is mainly GIS related]. The main objective for this analysis is to find the best location for the facility to support its future production. Important aspects are environmental impact over its lifecycle and proximity assessments (e.g. distance to public transport and other relevant public services).
2. Site analyses (for a defined site). Volumes, location (placement, orientation) of the building(s) on site. The main objective of the analysis is to identify the best placement of the facility and the project’s possibilities/limits with the given framework (municipality regulations, geotechnical conditions, important lines of sight and axes).
3. Building Survey (of existing conditions). Can be a Building Survey conducted by using traditional geometrical measuring of points and corner points, etc., using photogrammetry, 3D Laser Scans, or a technical condition survey (in Norway according to Norwegian Standard NS 3424 Condition Survey of Construction Works - Contents and Execution.
4. Building Programming. Complete client brief with spatial, functional and proximity requirements, and stakeholder and project framework constraints, etc. The result of this activity will ultimately be the “Requirement BIM”.
4.1. Building Functional programming (functional requirements and proximity, etc.). Defines functional needs to support the purpose of a facility and its future production.
4.2. Building Spatial Programming. Spatial requirements. Defines the functional and physical requirements for each spatial element in a building or facility. Both spatial requirements for the future occupant’s activities and relevant building and/or user required equipment. Usually requirements are limited to the net functional areas as the starting point of design, but as “supporting” areas appear (e.g. circulation areas and washrooms, etc.), requirements can be assigned.
4.3. Building Technical Programming. Technical requirements, in Norway usually stated according to NS3451. Defines requirements for all supporting building elements and systems to support the future occupant’s activities.
Design Stage
1. Architectural design competition and evaluation. The main objective for BIM requirements in an
D.1 Defining BIM Objectives (Informative)
Statsbygg – BIM Manual 1.2.1
63
architectural competition is to achieve easy, fast and equal assessment of the competition proposal. BIM is used for evaluating spatial layout, generic area, volume and quantity measurements, and also visualisation with a 3D terrain model (GIS). Note: BIM is NOT used for evaluation of the architect’s “aestetic expression”.
2. Basic BIM Design Authoring (baseline BIM for basic outline and starting situation, etc.). As a starting point for Design, Statsbygg exports a Requirement BIM with the project’s Spatial program containing requirements set to functions and spaces. Defined spaces with requirements are given a “dummy” geometry and will appear as a line of cube space object, e.g. a space with a programmed net area of 25 m2 will be exported as a space of 5x5m. Requirements relating to the space are assigned to the space as Property sets (Pset). Requirements set on a main and sub-functions level or other groups of spaces (e.g. security zones) are exported as IfcZone.
2.1. For architectural competitions, Statsbygg has provided a basic BIM as a modelling starting point for the contestants. The basic BIM has been made available as an IfcSite object of the competition area, usually also containing existing buildings as a reference for the competitors. In the Site, project origin and orientation has been set and neither of these should be moved by the contestants. This for geo-referencing purposes in order to enable objective 3 (and 4).
3. BIM – GIS Integration analysis and visualisation. BIM - GIS integration is mainly used in a very early conceptual stage of the projects, e.g. in architectural competitions. The analysis is (at Statsbygg) performed in a GIS tool, after referencing the BIM into the GIS file/database. The objective is to put the new building envelope/volumes and entry points in the planned landscape/context, for checking axes, lines of sight and the main entrance, etc.
4. Architectural Visualisation. A photorealistic presentation of the architectural design. Usually produced in the native CAD/BIM tool, or further developed in special software for the purpose. The objective to communicate the design to the audience and stakeholders, including the artistic/aesthetic aspects of the design.
5. BIM validation/Consistency check. For utilising BIM, it is important that the starting point for downstream analysis is a consistent BIM. Unless you know that the models are consistent, information derived from them cannot be trusted. Hence validation of the models that are to be used in analysis is the predecessor of most of the objectives in this chapter. Models should be consistent with regard to model structure, relationships and use of object classes/types and they should be checked for duplicates and intersections.
6. Quantity takeoff (QTO). QTO is performed at many different levels, at different design stages and for different purposes throughout the project’s/building’s lifespan. A properly authored BIM enables high quality and fast quantity surveillance. However, the quality of the quantities produced always depends on the quality of the input information, hence the most important characteristic of a BIM for QTO is consistency. The deliverable from quantity take-off is a bill of quantities, which is delivered for both cost estimating and other purposes. The results of quantity take-off are used in, for example, cost estimating, life cycle costing/assessment, scheduling and the calculation of CO2 emissions from materials in use, etc. There are two ways of identifying quantities from an open BIM. They can either be measured / analysed from the geometry of the objects or they can be read from the attributes of the object. There are advantages and disadvantages associated with both methods: while the first method is more complex, the latter one is more dependent on the BIM authoring tool having implemented the correct way of writing quantities to the different objects and the BIM author having modelled a consistent BIM. Rules of measurement are often subject to local regulations and standards, i.e. the quantities read from attributes will not necessarily be directly applicable for their purpose. The purpose of the QTO decides the requirement for the models, e.g. for costing you need,
D.1 Defining BIM Objectives (Informative)
Statsbygg – BIM Manual 1.2.1
64
in addition to a consistent BIM, the correct quantities and adequate identification of the objects. For calculating CO2 emissions from materials, you need to identify the volume or weight of each material in use, hence you need to know each object type’s material layers (and the geometry of each layer). In the conceptual stages, identification for QTO shall as a minimum be possible to obtain from naming the objects. For coordinated design, there shall be a type object following every instance. The name attribute of the type object shall be used (e.g. IfcWallType.Name), and all type names shall be unique for all types in use, i.e. all equal objects shall have the same type name, and all objects with the same type name shall be exactly the same building object type.
7. Designed Geometric 3D Inter-disciplinary Coordination.
8. Structural analysis.
9. Acoustical analysis.
10. Security and circulation analysis.
11. Fire safety analysis.
12. Energy analysis (energy use and thermal comfort).
13. Lighting analysis.
14. Accessibility analysis.
15. Environmental analysis (for certification like BREEAM and LEED, etc.).
16. Planned project scheduling and resource allocation (“4D” analysis).
17. Basic cost analysis (“5D” analysis).
18. Detailed cost analysis (“5D” analysis).
19. Building Code analysis.
Construction Stage
1. Construction adapted geometric 3D Inter-disciplinary Coordination.
2. Construction adapted quantity takeoff (QTO).
3. Planned vs. actual project scheduling and resource allocation (“4D” analysis).
4. Construction adapted cost analysis (“5D” analysis).
5. Project close-out deliverables analysis.
FM and operations stage
1. FM handover analysis.
2. Building operations scheduling analysis.
3. Building preventive maintenance analysis.
4. Asset management (space area and equipment inventory, etc.).
D.2 Analyses applied by Statsbygg (Informative)
Statsbygg – BIM Manual 1.2.1
65
5. Contingency planning analysis.
6. Environmentally hazardous products analysis.
7. Building disposal analysis.
D.2 Analyses applied by Statsbygg (Informative)
As a client Statsbygg is a buyer of design services and facilities that (within project limits and budget) shall
support our customers’/tenants’ needs and production in the best possible way. The ability to verify and
check that we receive what we purchase is one of the key factors of production and success. The
transparency in BIM projects enables us to do this in a better way.
Below we describe some of the possible analyses that can be carried out by using BIM, what experiences
Statsbygg has in these areas and the BIM requirements that we regard as being relevant for successful
analysis.
Typical modelling requirements that are important for downstream analyses include
Modelling structure (is the model assembled and exported correctly?)
Modelling consistency (has the modeller been modelling correctly?)
Requirements relating to the objects that shall be present in the model
Requirements relating to object information (attributes, properties, relations …), where naming conventions / classifications (tags) for unambiguous identification and type data are important
*
Analyses and BIM quality assurance processes in use at Statsbygg are:
Consistency check (Architectural and Structural)
Checking consistency in the models is an important “preparation” and predecessor for many of other
downstream analyses. Unless you can be sure that the analysed model is consistent, you cannot really
trust the results. A consistent model in this setting is a model with the correct/agreed structure that
follows naming conventions/classifications and has no (unintentional) duplicate or overlapping objects
(unless intended), etc.
Control of the individual discipline model should first be carried out in the native CAD/BIM authoring tool
in order to check that the correct tool/object type has been used (e.g. that a stair has been modelled as a
stair object, not as a series of slab objects), that layer and storey structures have been used correctly, and
as a visual check in order to ensure that any “draft objects” temporarily placed outside the building
envelope have been removed before export. Some CAD/BIM tools have built-in features for checking for
double / overlapping objects – they should be used if available (check with your local CAD reseller if in
doubt).
After export (to IFC) the individual discipline model should also be checked – as a visual check in an IFC
viewer and/or in a checking tool like Autodesk Navisworks and Solibri Model Checker (SMC).
Statsbygg will check the Architectural and Structural models in SMC for:
- Model structure: The models shall have a correct building and storey structure, and the building parts / objects shall have correct relations. All building parts shall have defined relations to the
D.2 Analyses applied by Statsbygg (Informative)
Statsbygg – BIM Manual 1.2.1
66
storey in which they reside, a window shall have relation to the wall in which it is placed (through an opening object in the wall) and the wall and window in the wall shall have relation to the same storey, etc.
- Required components / objects (and object type where relevant) shall be present. Requirements for objects will differ from phase to phase and from project to project, but should comply with the BIM manual for the client/project.
- “Legal” dimensions for certain object types should be observed (see figure). The “legal” dimensions and their tolerances can easily be adapted by changing the parameters in the rule set. Dimensions that can be checked include height, length, width, cross-sections/diameters, footprints and distance to next storey, etc. In principle all geometrical parameters are “checkable”. For the Architectural model minimum openings for windows and doors are checked.
Figure: The
illustration shows the “legal” dimensions a beam should have. In this case the parameters are set to a
minimum height/width of 50 mm, a minimum length of 100 mm, and a maximum length of 20 metres.
These parameter values are set according to need.
- The placement of components / objects (relative to other components): checks are made to ensure that objects do not “hang in mid-air” but are supported, e.g. that walls, columns and beams are supported (have touching objects) above and below them. The tolerances can be set as parameters (the default in SMC is usually 20 mm).
- In the rule set there is also a check for the distance between slabs, that can be used for setting minimum or maximum requirements for storey heights, e.g. for checking sufficient space for technical installations, or for checking government requirements for floor space ratios. For instance, a maximum permitted storey height may be set in the local area development plan (zoning plan). If the distance between slabs (storey height) exceeds a given height, a theoretical plan is defined for zoning plan calculations [no: Utnyttelsesgrad]. The consequence of this is that the real plans may be counted twice in the zoning plan calculations. Revealing this at an early stage could prove valuable for incorporating necessary changes in the design.
D.2 Analyses applied by Statsbygg (Informative)
Statsbygg – BIM Manual 1.2.1
67
- Collisions / overlapping objects in the model: the rule set checks to ensure if there are double or
overlapping objects in the model. This check is essential as a pre-check for quantity take-off and cost calculations, as quantity take-offs are based on the geometry of the individual object and do not take into consideration any overlapping or doubled objects. We have seen examples of double floor slabs of more than 9000 m3. Such volumes of concrete that are calculated twice obviously have a major impact on cost calculations. It is therefore very important that overlapping and doubled objects are identified and – if the deviations pass a certain level – are corrected in the model before making calculations. The rule set reports (as a table) the amount of overlapping that exists in respect of the different object types. The table shows the total volume of the overlapping object type, the overlapping volume and the percentage this represents.
- The Architectural model can also be checked for clashes with furniture, equipment and other modelled objects.
- Space object checks (Architectural model): this is an important pre-check before undertaking the area check – based on space geometry. The rule set checks that the Architectural model has space objects, whether the space objects overlap (with other spaces or building parts), whether they possess unique identifiers (numbers and/or names), whether the spaces have a minimum size (height and area, etc.). The analysis also checks whether all “cavities” in the model have been “filled” with space objects, and lists the amount of area that is not covered by space objects for each storey. Warnings are provided for spaces that do not touch the floor slab or do not extend to the bottom of the next storey floor slab. All parameters, tolerances and type of objects included in the check are configurable.
- If gross area space objects (“BTA” objects) are present in the model (usually a requirement in Statsbygg projects), we can also check that all spaces are located within the (gross area) BTA object. A space object is not allowed to be located outside of the BTA object or to be partly located in two different BTA objects.
- In Statsbygg projects a check will normally be made for “legal space denominations” – i.e. that the space objects have names according to an approved space name enumeration list. The space names (and their classification) is important in analyses for Accessibility [no:UU – Universell Utforming], security/circulation and fire egress analyses.
It is recommended that individual architects / structural engineers carry out separate consistency checks
on their own models at an early stage during the modelling process, as this will probably provide an
indication about whether one is “doing the right thing” when modelling – and early corrective action will
In SMC predefined consistency rule sets
exist for the Architect and Structural
models. For the MEP models there is
currently no rule set for checking
consistency.
For the Architect model two versions of
the rule set exist – “conceptual” and
“final”, roughly corresponding to the
outline conceptual and final conceptual
phases. For the Structural model only one
version exists. The rule sets may be used
“as is”, but more advanced multiple time
users may opt to configure their own rule
sets (using SMC’s “Ruleset Manager”)
according to their own BIM manual.
D.2 Analyses applied by Statsbygg (Informative)
Statsbygg – BIM Manual 1.2.1
68
always be easier and cheaper than corrective action that is forced later on during the modelling process.
Certain consistency problems may also be due to the IFC export of the CAD tool, but certified software is
expected to be able to export models that comply with the requirements mentioned. Some modelling
tools have internal features for checking their own model consistency and collisions.
Verifying design area (all projects)
Below we describe a simple check for Statsbygg’s BIM projects that can be carried out in two different
ways – each with its strengths and weaknesses. Individually – and particularly in combination – they
represent a major added value in projects and increase the efficiency of internal work processes.
1. Checking design area in Solibri Model Checker (SMC)
The primary strength of an SMC area check is the possibility available for checking the entire model while
simultaneously running a consistency check of the architectural model. After quality checking, areas can
be extracted by using the “Information Takeoff” (ITO) functionality of SMC.
This provides a quick and convenient overview of areas that are modelled as space objects, areas that lack
space objects and any overlapping space objects – as well as revealing the area of wall “footprints”.
Usually when planning such analyses we request a “gross area object” [no:BTA] to be present for each
storey, covering the entire space of the storey/elevation, including the area of external walls/curtain walls.
This provides a precise overview of the total area per storey in the architect-designed model. The
drawback is that it does not include direct access to the programmed area, so checking to ensure that the
design proposal meets the area requirements is a retrospective “spreadsheet exercise”.
This analysis depends on the models complying with naming conventions and/or numbering schemes
according to the client’s spatial program. If they do not do so, collating / connecting designed and
programmed areas will be a cumbersome and labour- intensive exercise. Required name/numbering
conventions can be gathered from synchronisation with the dRofus database that Statsbygg uses for
expressing its spatial/functional/building program requirements. The space names and numbering will
then be overwritten in the IFC file that is synchronised with the correct space function name/number.
2. Checking area by synchronising the architect design BIM with the spatial program in dRofus
The strength of this area check is the ability to list side-by-side programmed and design areas for each
function and space, with deviations also listed. The main disadvantage is that it does not reveal whether
the areas have been consistently modelled, i.e. that all designed areas have been covered by space objects
(IfcSpace), or whether space objects overlap. The check is limited to the footprint area of the spaces,
hence we are only able to check functional areas (and gross areas if modelled) – not the designed “usable
area” [no:BRA] (all area inside external walls) and gross areas [no:BTA] that are not modelled in the BIM.
This check requires that the models follow agreed naming or numbering conventions according to the
spatial program. If they do not do so, collating designs to the program area will be a labour- intensive
exercise. It is recommended that the model is also checked for consistency regarding “empty” and
overlapping areas in SMC.
Recommendation: Both A (SMC) and B (dRofus) interacting is preferable.
Clash Detection / Coordination
Clash Detection / “Collision Control” is an analysis that has since long provided added value in BIM
D.2 Analyses applied by Statsbygg (Informative)
Statsbygg – BIM Manual 1.2.1
69
projects. It is a rather low-hanging fruit that does not require information-rich objects. Basically the only
requirement is to keep track of the object geometry of the different disciplines (usually Architectural,
Structural and MEP).
Three main categories of this analysis are usually carried out:
1. Clash between the Architectural/MEP models or Structural/MEP models: the main purpose of
this analysis is to ensure sufficient space for technical installations / objects within the building
shell. During the early phases it is important to clarify that the technical components that affect
building construction do not clash with load-bearing elements. It is of course also important to
ensure that technical components have sufficient space around them (for assembly and servicing),
e.g. above suspended ceilings.
2. Clash between the Architectural and Structural models: the architect and the structural engineer
are partly working with the same objects in the building, so in this particular analysis the objects
are supposed to clash; ideally Structural slabs and Architectural slabs shall be located at the exact
same spots, similarly for columns, etc.
3. Clash detection between Technical models: This analysis checks clashes between the technical
models – Mechanical and Electrical (HVAC, piping, electrical power distribution and
communications, etc.).
For these analyses to be meaningful it is of paramount importance that all disciplines work within the
same coordinate system – i.e. that all models use the same origin (x,y,z=0,0,0), the same orientation
(Northing) and the same axes. It is strongly recommended that the designers test the exchange of the
discipline models at a very early stage and merge them to ensure a correct “starting situation”.
Accessibility analysis – Designing for Accessibility for All
This analysis mainly checks geometry requirements related to the design of buildings for the purpose of
ensuring practicability / accessibility for all people – including people with disabilities. The is denoted as
• Proper designation of security level (zones). This can also be manually assigned in SMC, but should be defined in the BIM authoring tool or in the client’s requirements database (for Statsbygg, dRofus).
Acoustical Analyses
Statsbygg currently does not have experience with BIM-based acoustical analysis, but some of the acoustical analysis tools in common use are now able to read geometry exported from CAD/BIM design tools. This implies that 3D geometry from a BIM can now be reused in acoustical analysis.
These analyses are often based on reflection from – or transmission through - simple surfaces. It is hence expected that the architect’s models need to be simplified rather than detailed before an analysis, as complex / detailed geometry does not necessarily produce better / more correct results than a simplified surface model. On the contrary, it often the case that too many details in a model may lead to less accurate acoustical prediction results.
In the following description the acoustical analyses are divided into two parts: room acoustics and sound insulation. Noise control from internal or external noise sources can be treated together with either part, but currently no experience of this exists in relation to BIM.
Room acoustics
For a successful room acoustical analysis the model of the space in question needs to be “watertight”. In order to prevent acoustic waves from “leaking”, all internal spaces must be “closed” in a way that resembles how the design solution is intended to be built. A “simplified geometric model” implies that equipment, furniture, slender columns, window frames, door handles and railings, etc. should not be included in a model exported for acoustic purposes, unless the sheer size of such components is such that it can be expected to influence the acoustics of the space in question. In such cases the geometry should be simplified using suitable CAD tools before export. Examples of this may be bookshelves in a library or a large sculpture in a hall. Curved surfaces should be divided / exploded into a suitable set of plane surfaces. For such purposes some kind of “middleware”, like Google SketchUp or similar, may be suitable if such features are not available from within the CAD system in use in the project.
D.2 Analyses applied by Statsbygg (Informative)
Statsbygg – BIM Manual 1.2.1
72
Figure 1:
Example of a room acoustical analysis model (in ODEON) imported from IFC via SketchUp. Curved surfaces are
simplified to produce a suitable set of plane surfaces. The colours indicate materials with different sound absorption
data. (From BIM project: “Midtbygda skole”)
Possible “production track”: a simple BIM containing walls, slabs, doors, windows and space objects is exported to IFC (.ifc file). In some models it may be necessary to include more objects, e.g. beams, columns, stairs. The model is imported in SketchUp for pre-processing / simplification (converting curved surface and, removing insignificant geometry, etc.), and then exported to ODEON in a text format (.Par file) for acoustical analysis. For very large building models a part of the preparation may involve cutting out the relevant space from the total model. The selection of surface materials is currently assumed to be made within the acoustical analysis tool because the related acoustical data are normally provided by the acoustician (RIAKU).The description of intended surface materials is potentially information that could be included in the BIM and extracted from the BIM. The material data for room acoustical analysis are absorption coefficients in octave bands and scattering coefficients (in octave bands or as a single number at mid-frequencies).
Sound insulation
For an acoustical analysis of sound insulation a simplified 3D building model with walls and floors is needed. This can be created from a 2D plan or by exporting the space objects in the IFC format to the acoustical software for sound insulation calculations. Currently, some of the more advanced software for sound insulation analysis may be SONarchitect ISO (http://www.soundofnumbers.net/).
The acoustical requirements may vary from room to room, and also depend on the types of neighbouring rooms (e.g. living room, kitchen, stairway and common areas, room for building services equipment). All or part of this information can be contained in the BIM (in the ifcSpace object) and exported to the acoustical software. This requires:
- Each room having a room type
- Each room type having a collection of requirements
- Each requirement may be associated with another room type, with Outdoor, or with any room space
- Each requirement must be associated with a parameter. A parameter is the evaluation of any acoustic quantity, either a weighted value or a single frequency band.
- Each requirement must be associated with a limit, i.e. a constraint value that the calculation must not exceed.
For the acoustical analysis of sound insulation the simplified 3D building model must be supplemented with data for the acoustic properties of all the BuildingElements:
- All vertical BuildingElements (IfcWall, IfcDoor, IfcWindow) must have an associated one-third
- All horizontal BuildingElements IifcSlab,IifcRoof, IfcStair, IfcRamp) must have both one-third octave band sound reduction index R and normalised impact sound pressure level Ln
- All vertical coverings (IfcCovering) must have an associated one-third octave band improvement of the sound reduction index ΔR
- All horizontal coverings IifcCovering) must have both one-third octave band improvement of the sound reduction index ΔR and reduction of the impact sound pressure level ΔL
- All ventilation ducts must have either an associated one-third octave band sound reduction index R or a normalised level difference Dn,e
- The faces of all BuildingElements with significant areas must have an associated one-third octave band absorption coefficient α
Figure 2: Example of an acoustical analysis model of sound insulation between two rooms in a series of two-storey
terraced houses (SONarchitect ISO).
Possible “production track”: a simple BIM containing walls, slabs, doors, windows and space objects is exported to IFC (.ifc file). A simplified building model is created, e.g. based on the space objects. Each room is assigned a room type, which is used for the definition of the acoustical requirements. The room type and the acoustical requirements can either be integrated in the BIM or assigned by the acoustician as part of the acoustical analysis.
The selection of surface materials is currently assumed to be made within the acoustical analysis tool because the related acoustical data are normally provided by the acoustician (RIAKU).The description of intended materials is potentially information that could be included in the BIM and extracted from the BIM.
In addition to the above mentioned BuildingElement data, the acoustician can apply different solutions for the junctions, either rigid or elastic. This can influence the calculation results significantly, and thus this represents additional information that must be reported together with the results of the acoustical analysis.
Currently it is not clear how the data for junctions should be contained in the BIM.
Model requirements:
For acoustical analysis each space in the model must be ”closed” / ”watertight”
The following objects shall be included:
o From Full Conceptual Design: walls with acoustical properties (airborne sound insulation
and sound absorption)
D.3 Building Information Modelling Practice (Normative)
Statsbygg – BIM Manual 1.2.1
74
o From Full Conceptual Design: slabs with acoustical properties (airborne and impact sound
insulation and sound absorption)
o From Full Conceptual Design: windows and doors with acoustical properties (airborne
sound insulation and sound absorption)
o Stairs
The following objects may be included, if important for the acoustical simulation:
o Major columns and beams (assumed to have acoustical impact)
o Equipment and furniture shall - generally speaking - not be included. However, if they have
”large” dimensions assumed to have acoustical impact, they should be included
Objects with detailed geometry should be removed or simplified before export
o Objects with “small” dimensions should not be included in the model for acoustical analysis,
as this complicates the analysis, can increase calculation time drastically, and may require
more follow-up work / housekeeping in the analysis tool. Typically this will include “slender”
columns and beams, equipment and furniture and railings, etc.
*
INFO: Translation of terms from Norwegian to English – reference (ISO 717-1 and ISO 717-2):
o NO: Veid feltmålt lydreduksjonstall, R’w
o NO: Veid feltmålt normalisert trinnlydnivå, L’n,w
o EN: Weighted apparent sound reduction index, R’w
o EN: Weighted normalised impact sound pressure level, L’n,w
Figure: Example of an acoustic analysis model (in Odeon) - curved surfaces are simplified to produce a suitable set of plane
surfaces.
D.3 Building Information Modelling Practice (Normative)
This chapter contains Statsbygg’s view of what is regarded as being normative BIM practice wherever
feasible, subject to project constraints and approved CAD/BIM tools.
Because a BIM (a digital model or a process) always serves a purpose, it is crucial that the model is
unambiguous with the expected components in place. This is managed by the requirements set in every
phase or in a business process.
To enable sufficient benefits to be derived from the BIM during the production phase (construction), the
model should have a production centric logical structure – i.e. the model should mimic the way the
contractor actually constructs – e.g. walls are built floor by floor and should not be modelled over multiple
D.3 Building Information Modelling Practice (Normative)
Statsbygg – BIM Manual 1.2.1
75
stories. Key information for the contractor includes quantities and geometry (production centric logical
modelling).
Before starting modelling
1. Examine the BIM delivery plan for the project.
2. Make a plan for using the model within the relevant phase. Focus on what is important for the project while design is ongoing. Make agreements about what models content shall be presented in design reviews
3. Check to ensure that BIM deliverables and requirements are relevant for defined project decision points.
4. Check to ensure that BIM objectives (the intended purpose / usage of the BIM) are communicated and understood by the project participants, including the modellers.
5. Check to ensure that the modelling tools (CAD tools, etc.) have relevant and sufficient support for fulfilling the BIM requirements.
6. Organise a session where all disciplines/domains are present and interact by exchanging models across selected software tools in the project.
6.1. Make a test model involving all disciplines. Check that it is feasible to model according to the requirements in the intended modelling tools. Find alternative approaches for requirements that cannot readily be accounted for.
6.2. The session shall basically reveal any technical issues and ensure that all disciplines can start modelling. However the exchange of known issue experiences is just as important.
7. Establish a contact list for the software solution providers involved, to ensure intended use of the software and continuous documentation of technical errors and deficiencies if any problems arise.
8. Establish an interaction platform where all project participants can access the latest version of the model(s). This may be file-based through a web hotel or similar structure – or it can be done by using a model server.
9. Clarify all interfaces between disciplines / participants, including the content information of each of the partial (discipline) models.
10. Establish new, more efficient working processes when working with BIM.
10.1. Identify which working procedures that can be omitted when using BIM in the project. Quantity takeoff and area checking are two goog examples of processes that is done more efficiently with BIM.
How to make a good model
1. Consider the consistency / structure / composition of the model.
2. Model consistency is the key for making it useable and useful for downstream processes. If the model has critical structure errors the model information cannot be trusted.
3. Use the correct object type – reflecting the actual function of the object. It is possible to model an entire building using only the wall type object, but doing so will render the model almost useless for downstream processes.
4. All objects in the model shall be sensibly grouped.
5. The model shall distinguish between type objects and occurrence (instance) objects.
6. The model shall distinguish between generic and product specific information (properties etc.).
7. The model shall be without “loose ends” or objects without relation to other objects.
8. Duplicated and overlapping objects shall be avoided. This should preferably be checked within the modelling tool before BIM export.
9. The GUID (global unique identifier) for each occurrence shall be preserved when updating the model e.g. by moving an object from one location to another, or when the orientation of the
D.3 Building Information Modelling Practice (Normative)
Statsbygg – BIM Manual 1.2.1
76
object is changed.
10. This will make model versioning and tracking changes in the model easier. Some CAD tools may currently not fully comply with this requirement – actions to mitigate this in the project must be planned, and accepted by project management.
11. Observe correct relations between objects. Most relations will probably be automatically generated in the CAD tool, so using the CAD tools correctly is important. In practical modelling selecting the correct object tool for the intended function (wall tool, slab tool, stair tool and space tool, etc.) and working from the correct floor when placing the objects may be important.
12. Other important relations are zones (the grouping of space objects) and systems (the grouping of (mainly technical) objects).
13. Observe the use of text fields in object attributes and properties – if naming conventions for object names and type names, etc. are be used in the project, it is important to comply carefully and strictly with the established standards and enumeration lists, etc. to enable downstream use of the BIM.
14. Restrict the use of object properties to the actual requirements / detailing in each phase of the project. The use of excess properties in early phases will “clog up” the model by making it unnecessarily large and complex, and may trigger unnecessary re-design in the project.
15. Check the model in-house before it is exported and shared with other disciplines. Most CAD tools have some sort of quality checking features – they should be used! A third party model viewer or model checker may often prove useful for “weeding out” the worst errors. The acquisition of a tool for finding model errors is highly recommended.
Common modelling mistakes and misconceptions
By modelling mistakes we mean deviance from our BIM requirements, usually elements in the IFC model.
The source of errors either comes for the user or the CAD-software. A mistake made by the user is often
the result of ignorance about the BIM deliverables and the following requirements or how to use the CAD
software in the best possible way. This can be solved by providing good documentation and guidelines for
the user.
Model errors caused by the CAD software could be bugs or poor implementation of the IFC-schema.
However, the main source of deviance usually relates to the fact that our requirements are not always
compatible with the internal processing of models in every CAD system. The ideal world is too far from the
real version. This results in frustration and filling the gap in the middle of the project is a very time-
consuming process. Some of this can be fixed by following the advice in the chapters above.
This chapter will address some of the mistakes we see in our everyday projects. The list is not complete
(we suggest that a website forum or wiki could deal with such common mistakes by serving as a “how to”
database for projects using open BIM). However, we will try to focus on those user-initiated mistakes that
can be fixed.
Object Identification
Statsbygg intends to pursue the current requirements relating to identification of IfcProject, IfcSite,
IfcBuilding and IfcBuildingStorey. These are common object types where GUID and the name must be the
same in all models. We are aware of problems regarding keeping the IFC-GUID in some applications.
However, this will make correct naming essential.
Identification and naming conventions for objects like IfcProject, IfcBuilding and IfcBuildingStorey can
easily be resolved by exporting all the elements with the right conventions from one model to IFC and
then importing the file into all other models as groundwork. This procedure can also help with the
D.3 Building Information Modelling Practice (Normative)
Statsbygg – BIM Manual 1.2.1
77
coordination of defining the project zero and adjusting floor heights, etc.
Since the IFC specification does not cover every construction type or element, naming conventions and/or
proxy elements are useful. But this implies that other attributes must contain valid names and codes.
Please ensure that you apply the right set of names/codes if such is specified. Please be aware of case
sensitivity.
Naming and numbering of spaces
The rooms object (IfcSpace) is used in several databases. The primary key is the room function number
(RFN), which is a database ID for every planned room. This is handled in the requirement chapter.
Figure 1: Spaces are not recognised due to incorrect naming/numbering
Tidying up around the model
Figure 2: Irrelevant objects "scattered" around the model should be removed before IFC export. This may imply removing certain CAD layers before IFC export
D.3 Building Information Modelling Practice (Normative)
Statsbygg – BIM Manual 1.2.1
78
Relations between objects
Figure 3: Column and wall are not related to the floor on which they physically belong
The object consists of multiple construction building parts
Figure 4: Wall object is both external and internal wall, causing errors in QTO and energy analysis
Object class/type based on function
When modelling an object, it might not be obvious what kind of entity it represents in the IFC schema. We
recommend that the modeller should use an entity based on the function of the object. If a building has a
glass floor, the entity is IfcSlab, not IfcWindow.
D.3 Building Information Modelling Practice (Normative)
Statsbygg – BIM Manual 1.2.1
79
Roof window [no:overlysvindu] – IfcWindow
Inspection hatch [no:inspeksjonsluke] – IfcDoor
In other examples the object type is completely wrong, and has obviously been created in another tool
than the intended one.
Figure 5: If the object has an incorrect object class it may still produce a decent 3D representation, but the model quality is reduced, creating a detrimental impact on QTO, egress, security and circulation analyses
Property Sets
Use of proprietary PSets (such as “PSet_CAD_Application_Dimensions”), when there is a standardised
property in the IFC specification, is not a very interoperable way to work with data. Mapping tables and
export filters should be used to avoid superfluous properties and information.
Dispense with proxy elements in the model
By Proxy elements (IfcBuildingElementProxy) we mean objects without classification. This can be a part of
other construction elements or technical objects, but often they appear as furniture and other inventory.
The good thing about Proxy elements is that they are very flexible can represent anything in the model,
e.g. if space-intensive units like art installations and machinery for production, etc. can be given a
geometrical boundary representation to ensure enough space during the early design stages.
The catch with using proxy elements is that they do not have any built in properties or relations that are
useful in a downstream process.
Space program vs. Space functions
Space programs are not a standard hierarchy of functions, and the space programs can vary between
projects, e.g. spaces can be oriented by department and section, building and story, main functions and
D.3 Building Information Modelling Practice (Normative)
Statsbygg – BIM Manual 1.2.1
80
sub-functions. For example, WC can be a part of a the main function, Administration.
If the space program differs from space functions in the model, the space classification must be done
manually. Either by generating functions in the CAD application and tag spaces, or by sorting the spaces in
Functional zones.
D.3 Building Information Modelling Practice (Normative)
Statsbygg – BIM Manual 1.2.1
81
E. Building Information Modelling spin-off deliverables
(Informative)
In addition to the BIM deliverables a number of “reports” from the BIM may be required.
Ref.# Subject Type Requirement and description
A. Drawings in
general
INFO
INFO
Please refer to Statsbygg CAD Manual “PA 0603 DAK-
LEV Supplier (in general) Leverandør av varer og tjenester til
byggverket (generelt)
(MERGE) “Merge” is not actually a participant role for persons, but is used to indicate that a BIM consists of models from more than one discipline that have been merged (collated / united) – usually a merged BIM consists of models from all relevant disciplines in the situation.
”Merge” er ikke egentlig en rolle for
personer, men benyttes for å angi at en
BIM består av en samenslått modell
med flere enn ett fagområde - normalt
består en merget BIM av modeller fra
alle relevante fag i den aktuelle
situasjonen.
7 http://www.omniclass.org
8 Electrical Engineering includes Electrical Power Engineering, Communications Engineering, Building
Automation Engineering and Vertical Transport Engineering (elevators etc.)
9 Elektroteknikk inkluderer Elektroteknikk, Tele- og automatiseringsteknikk, og Interntransport (heiser mv)